I drove to Indianapolis Monday, December 7
to attend the baseball winter meetings. As I drove south on I-65 through the
beautiful cornfields of central Indiana, somewhere near Rensselaer, on the
east side of the interstate, I encountered a huge wind farm, with dozens and
dozens of huge wind turbines stretched out as far as the eye could see.
(Made me think of a 50s sci fi movie.) They were all in motion at a moderate
pace, as there was approximately a 10-mile-an-hour wind. No big deal. But
after two days of watching 30 general managers try to make deals on cocktail
napkins while avoiding the press in the hotel bar, it was time to drive back
to Chicago. As you may recall, Wednesday, December 9, was the
snowstorm/blizzard across middle America, with winds howling from Wyoming to
the eastern seaboard. So, while driving back home north on I-65 around noon
with the winds gusting at over 50 MPH, I was looking forward to observing
the wind turbines spinning around madly like my electric meter in the summer
with the AC running full out. But when I drove past the "farm," guess what?
THE WIND TURBINES WERE ALL TURNED OFF, DEAD STILL, SLEEPING AT THE SWITCH,
HIBERNATING, LOCKED DOWN AND STOPPED COLD. All I could think of was that
this had to be the biggest lost opportunity of all time due to some goofball
accidentally throwing the wrong switch at windmill command. Or could it be
that these big turbines can't handle it when the wind comes whipping off the
plains?

 Mike Murphy, Chicago

Cecil replies:

We'll get to your question in a second, Murph. But first we'd better tackle
one sure to have some Straight Dope readers scratching their heads: since when
is there
a big wind farm visible from I-65 near Rensselaer?

Since about five weeks ago, that's when. (Other facilities have been operating for longer times elsewhere in the state.) I'm guessing you saw the wind
farm operated by Horizon Wind Energy at Brookston, Indiana, roughly 25 miles south of
Rensselaer, which was
dedicated November 19. This impressive installation has 121 wind
turbines and can generate 200 megawatts, enough to power 60,000 homes  and
that's just phase 1. Phases 2 through 4, expected to be completed by October
2010, will push the output to 500 megawatts. The long-term plan, which
depends on boosting transmission capacity, is for
660 turbines generating 1,000 megawatts spread over 100,000 acres.

If you're thinking all this alternative energy seems uncharacteristically
progressive for a place like Indiana, you need to get with the times. Wind
power has become a big business, and the wind doesn't blow only in blue states. A major center of wind
power generation is west Texas; Horizon's headquarters is in Houston. Most
of the company's 21 wind farms are in central U.S. states ranging from
Oklahoma to Minnesota. While the breeze in Indiana is less
formidable than some places, it's reasonably steady, and the I-65 location has the advantage
of being midway between two major centers of electricity consumption, Indianapolis and
us.

On to the heart of the matter: why lock down the
turbines when the breeze is really blowing and you could pump out some
serious juice? You've already guessed the reason: for fear the big windmills
will rip themselves apart if the gale gets too fierce. The danger isn't
strictly theoretical  check out the
Danish wind turbine
accident on YouTube. Horizon's turbines start generating electricity
when the wind reaches 6 to 9 MPH and reach maximum output at 22-25 MPH. They
automatically shut down above 42-44 MPH, known in the business as the cutout
speed. When wind speed drops below that level, operation automatically
resumes.

To restless minds such as ours, Murph, this doubtless seems a regrettable
waste. It's all very well to have your turbines rotating in a desultory
manner in some 10-MPH zephyr, but we've all watched enough Discovery Channel
specials to know nature's real power lies in storms. Isn't there some way to
harness those?

I put the question to Bill Whitlock, director of development for Horizon's
Great Lakes region. His answer: storms with high winds like the one we had
earlier this month are brief and relatively rare; you need to design the system for
average conditions. Despite shutting down when the winds are particularly
fearsome, midwestern wind farms typically generate 30-35 percent of
theoretical maximum output. Texas wind farms, for comparison, generate 40-45
percent.

Then again, conventional power plants commonly operate at 80 to 90 percent
of capacity, so the wind industry has a distance to go. One goal of wind
turbine research is to increase the cutout speed, and once you get past that
you've still got the problem of where and how to store the energy a storm
would generate. Still, after two hours digging out the driveway, it'd be
nice to able to think: at least we're a couple gigawatts to the good. Not to
mention the fact that 660 turbines spinning like garden pinwheels would be a
sight to behold.